Burst control for automatic rifles



March 28, 1961 c. w. LAMBERT BURST CONTROL FOR AUTOMATIC RIFLES 2 Sheets-Sheet 1 Filed March 27, 1959 H N r. m

INVENTOR. M

March 28, 1961 Filed March 27, 1959 C. W. LAMBERT BURST CONTROL FOR AUTOMATIC RIFLES 2 Sheets-Sheet 2 IN V EN TOR.

BURST CONTROL FOR AUTOMATIC RIFLES Chandley W. Lambert, 6325 Mackenzie Road, North fllmsted, Ohio Filed Ma 27, 1959, Ser. No. 802,370

3 Claims. (Cl. 89-129) The invention relates to burst control for automatic rifles in which the control acts to stop the burst after a predetermined number of rounds have been fired. The invention uses only one control cam and an indicator which can be set for any desired number of rounds per burst. The device can be made small, compact and light weight and can be adapted to any automatic rifle.

In the drawing the parts are shown much larger than actual size for the sake of clarity.

Fig. l is a longitudinal cross section of the invention showing the location and operation of various parts.

Fig. 2 is a cross section along the line 2-2 of Fig. 1 showing in detail the construction and operation of cam wheel 44 of Fig. 1.

Fig. 3 is a detail in which one element of Fig. 1 is rotated for greater clarity in exposition.

Fig. 4 is a cross section along the line 44 of Fig. 1 showing in detail the operation of ratchet wheel 30A by slider 63.

Fig. is a cross section along the line 5-5 of Fig. 1 and Fig. 6, showing in detail the projection 53 secured to frame 14 of Fig. 1. Superimposed are shaded portions 5)-54-52 of handle 48. These portions are shown in two positions-at S (safe) and at A (full automatic).

Fig. 6, which is a cross section along the line 66 of Fig. 5, shows the portions 50-5452 at position A of Fig. 5.

In Fig. 1 the sear rod 1 is connected to a retractable hammer (not shown) which is actuated by the movement of a chamber closing bolt (not shown).

The scar 2 is secured to sear rod 1. 3 is the location of scar 2 at the instant of firing. Sear spring 4 is compressed between frame 14 and collar 4A which is secured to rod 1.

Sear bar 5 moves to position 6 by action of spring 7 which is compressed between frame 14 and collar 7A which is secured to sear bar 5. Collar 8 is secured to bar 5 and moves to position 9 when sear bar 5 moves to the right to stop the firing action.

Each time the hammer is retracted 'by rearward movement of the bolt, the sear 2 rises to the top position, compressing spring 4. Each time the bolt closes the chamber, the hammer falls unless it is held back in the cocked position by sear bar 5 in position 6.

Tube or sleeve 10 is loose on bar 5. Hook 20 of latch 18 engages collar 8.

To tube 16 are secured a collar 11A for compression trigger spring 11, a latch spring 19, trigger 12 and collar 15. Trigger 12 slides in slot 13 in frame 14. Collar 15 has a pivot pin 16 for latch 18. The latch 18 is held against shoulder 17 and collar 8 by latch spring 19. 20 is the latch hook and 21 the heel of latch 18.

To adjusting shaft 22 are secured a collar 27A for forward clutch spring 27, collar 29, adjusting wheel 47, and handle 48.

To forward clutch tube 23 are secured ratchet wheel hub 30, collars 35 and 36, and forward clutch plate 25.

To rear clutch tube 24 are secured clutch plate 26, and

- 2,976,77i lag Patented Mar. 28, 1961 cam wheel 44. Rear clutch spring 28 is compressed between rear clutch plate 26 and the inner frame 14A. Clutch plates 25 and 26 are held together by springs 27 and 28. Movement of either plate disengages the clutch.

Between collars 35 and 36 is loose collar 37 to which pin 38 is secured. Clutch operating lever 39 straddles pin 38 and pivots on pin 40 in bracket 41 which is secured to the frame 14. Lever 39, the clutch operating lever, is actuated by pin 42 in bracket 43 which is secured to and moves with sear bar 5.

To cam wheel 44 is secured a lug 45. Lug 46 is secured to adjusting wheel 47. Lugs 45 and 46 are extended so that they may contact but not pass each other. Lugs 45 and 46 form an adjustable stop and they are in contact at the start of a burst. The movement of ratchet wheel 38A separates the lugs by rotating wheel 44.

The ends of spring 58 are secured to wheels 44 and 47. Spring 58 tends to pull lugs 4546 together into contact whenever the clutch plates 2526 are separated. Lugs 45-46 are connected to concentric wheels 44-47 and rotatable in the same orbit thus forming a manually adjustable stop which is adjustable in relation to a nonrotating part of the mechanism-specifically latch 18. This is the fundamental and basic idea of the invention.

To handle 48, which may move with shaft 22 to position 49, is secured post 50 which carries pointer 51. The hub 52 of handle 48 has radial ridges and grooves which cooperate with similar radial ridges and grooves in the face of fiat projection 53 which is secured to frame 14.

Beveled projections 54 and 55 on parts 52 and 53 come together when handle 48 is turned to the extreme right position and pointer 51, Fig. 5, arrives at A (full automatic). In this position handle 48 is held in position 49, compressing springs 2728 and collar 29 holds tube 24 and clutch plate 26 to the left disengaging the clutch. In this position post 50 on handle 48 contacts limiting lug 56A which is secured to the frame. When handle 48 is turned to the extreme left position to S (safe), post 50 contacts limiting stop 56 on the frame.

Cam face 57 of cam wheel 44, Fig. 2, can contact heel 21 of latch 18 and, Fig. I, raise latch hook 20 from collar 8 thereby releasing bar 5 and allowing spring 7 to snap bar 5 to position 6, closing the sear and stopping the firing action with sear 2 in the cooked position.

Spring 58 tends to reset the stop action cam wheel 44 by bringing lugs 45 and 46 together whenever the clutch is disengaged which is whenever plate 25 moves to right or plate 26 moves to the left. Spring 58 however cannot rotate adjusting wheel 47 and handle 48 out of the set position. The position of lug 46 can be changed only by manual operation of handle 48. Whenever handle 48 is turned manually the clutch is disengaged briefly and spring 58 tends to rotate cam wheel 44 and bring lugs 45-46 together.

Referring to Fig. 1, wheels 47 and 48 are both secured to shaft 22. On the hub 52 of hand wheel 48 are radial ridges and grooves which make fitted contact with similar ridges and grooves on the face of projection 53 which is secured to frame 14. In order to rotate, wheel 48 must move to the left to pass the ridges of the one over the ridges of the other. However any movement of shaft 22 to the left is resisted by the combined pressure of springs 27 and 28. Thus considerable force must be applied by hand to turn wheel 48 and with it wheel 47. On the other hand, cam wheel 44 can turn very easily when clutch 25-26 is disengaged. As a result spring 58 spins the much easier turning wheel 44 bringing lug 45 into contact with lug 46.

To adjusting wheel 47 is secured an L-shaped bracket 59, Fig. 1. When pointer 51 is turned to S (safe), bracket 59 is interposed between bracket 60 which is nism non-operative.

In Fig. 3 the slider 63 of Fig. 1 is revolved to show the fian'ge 62. Rocker arm 32 of Fig. 1 is secured to loose ring or collar 31. In Fig. *3 the forked ends 61 and 61A of arm 32 straddle the flange 62. Rod 64 is connected to the bolt actuating mechanism so that when the bolt slides to the rear the slider 63 also slides to the rear or left in the drawing. Flange 62 may be straight "as indicated by the broken lines, Fig. 3, or curved as shown by the solid lines 62.

The action of rocker arm 32, Figs. 1 and 4, and spring pawl '33 moves the ratchet wheel 3itA one tooth for each firing cycle. The curved flange 62 of Fig. 3 causes this movement of the ratchet wheel to occur early in the firing cycle and gives the maximum time for cam 57, Fig. 2, to unlatch the hook '20, Fig. 1, from collar 8 and stop the action by engaging the sear. Spring pawl 34 prevents backward motion of the ratchet wheel 30A.

By turning the handle 48 so that pointer 51 is at say #6 on dial 65, the burst control is set for bursts of siX rounds'each. When the trigger 12 is pulled to the left to the position shown in Fig. l, the sear is disconnected and sear spring 4 starts the firing action by pulling down sear rod 1 which is connected to the hammer of the rifle. As the firing continues ratchet wheel 30A turns :cam wheel 44 so as to separate lug 45 from lug 46 and compress spring 58. Cam 57 moves around through successive positions toward the heel 21 'of latch 18. After the 6th round is fired, lug 45, Fig. 2, has reached position 45A and the cam 57, having passed through the same angular displacement, has contacted heel 21 of latch 18 thereby unlatching hoolcZtl, Fig. 1, from collar 8 onsear bar 5 which moves to position 6 resetting the scar and the burst ends. 7

.As the sear bar 5 moves to the right the clutch is disengaged and spring 58 immediately brings wheel 44 back around so that lug 45 contacts lug 46. The setting of lug 46 is determined by the setting of pointer 51.

Note that the angular displacement between the teeth of ratchet wheel 30A should be the same as the angular displacement between the positions on dial 65. It is also equal to the angular displacement of the radial ridges and grooves on the faces of the cooperating parts 52 and 53.

In Figs. 2-4-5 of the drawing the angular displacements referred to are'shown as ten degrees in each case. However any other angle could be used depending upon the number of teeth-in ratchet wheel 30A,.which in this drawing is thirty-six. One thirty-sixth of 360 degrees is ten degrees. If the trigger is released before the entire set burst is fired, the clutch is thereby disengaged by action of lever 39 and spring 58 immediately resets the burst control for the full length burst indicated by the pointer 51 regardless of how many rounds were fired in the previous burst. At the end of each burst the trigger is released and latch 18 hooks on to collar 8 at position 9. When the trigger is again pulled a new burst starts.

Note that the forces transmitted by the various parts and operations are relatively small. The invention can be made many times smaller than the drawing and adapted to any automatic rifle.

When properly miniaturized, the device easily fits into a recess in the rifle grip or into the rear of the receiver. Burst control has several advantages, such as economy of ammunition. The greatest advantage is the effective ness of aimed cluster 4; Full automatic is always available at .a twist of the handle. I

I claim:

1. In a burst control mechanism, a spring actuated sear rod; a spring actuated sear bar cooperating with said sear rod; a trigger disconnectably attached by a spring actuated latch to said sear bar; a clutch operating lever pivotally connected to said sear bar; a forward clutch tube rotatable on an adjusting shaft and limitedly slidable by said clutch operating lever on said shaft; aratchet wheel secured to said forward clutch tube; a spring pawl pivoted on a rocker arm and operating on said ratchet wheel; a forward clutch plate secured to said forward clutch tube; a rear clutch tube rotatable on said adjusting shaft; a rear clutch plate and a .cam wheel secured to said rear clutch tube; said cam wheel cooperating with said latch; compression springs cooperating with said clutch plates; an adjusting wheel secured to said adjusting shaft coaxially to said cam wheel; a lug secured to said adjusting wheel and alug secured to said cam wheel; a spring attached to said cam wheel and to said adjusting wheel; said spring tending to bring said lugs into contact; a collar secured to said adjusting shaft between said clutch tubes; a manually adjustable hand wheel secured to said adjusting'shaft; and a flanged guided slider cooperating with said rocker arm.

2. In an automatic rifle,-a burst control mechanism comprising a spring actuated sear rod and a spring actuated sear bar; a trigger secured to a sleeve slidable on said sear bar; a disconnectable spring latch connecting said sleeve to said sear bar; a rotatable cam cooperating with said latch; a manually operable hand wheel and attached indicating pointer positionally cooperating with an adjusting wheel and attached lug; said lug cooperating with a second lug attached to said cam; a spring secured to said adjusting Wheel and to said cam; a rotatable ratchet wheel connected by a clutch to said rotatable cam; and a clutch operating lever connected to said clutch and to said sear bar, said hand wheel and said adjusting wheel being secured to a central coaxial adjusting shaft.

3. In an automatic rifle a burst control mechanism comprising, a manually adjustable wheel secured to an adjusting shaft and a protruding lug secured to said wheel; a rotatable cam wheel loose on said shaft and coaxially adjacent to said adjustable wheel; said cam wheel having a protruding lug engageable with the said lug on said adjustable Wheel; a spring secured to said 'adjustable'wheel and to said cam Wheel; said spring tending to bring said lugs into contact with each other; a ratchet wheel loose on said shaft and rotatably connected to said cam wheel by a detachable clutch; intermittent rotative movement of said ratchet wheel being transmitted to said cam wheel by said clutch and tending to separate said lugs on said adjustable wheel and said cam wheel by additive increments; a spring pawl, secured to a rocker arm, acting upon said ratchet wheel; and a spring actuated sear bar retractable by the motion of a trigger acting through a disconnectable latch; said sear bar being connected by a clutch operating lever to said clutch; said cam wheel being engageable with said disconnectable latch so as to disconnect said sear bar from said trigger.

References Cited in the file of this patent UNITED STATES PATENTS 2,887,012 Kunz May 19, 1959 FOREIGN PATENTS 297,450 Switzerland June 1, 1954 Jewe W 

